#include<stdio.h>
#include<string.h>
#include<stdlib.h>
//最大 2変数
int min(int a,int b){

    if(a>=b){return b;}
    return a;
}



int main(void){
int x,y,z;
scanf("%d %d %d",&x,&y,&z);

for(;;){
    if(z==0){break;}
    if(x==y){break;}
    else if(x>y){y++;z--;}
    else{x++;z--;}
}

if(z==0){printf("%d\n",min(x,y));}
else{
printf("%d\n",min(x,y)+z/2);}

}